Abstract: A heater is built in an inner sleeve of an electron gun, and an impregnated type cathode is fixed at an end portion, on the grid electrodes side, of the inner sleeve. The inner sleeve, having an outside diameter ranging from about 1.0 mm to 1.4 mm and a length substantially equal to a primary spiral length of the heater is inserted in an outer sleeve. The outer sleeve has on the grid electrodes side a small-diameter portion having an outside diameter ranging from about 2.2 mm to about 2.6 mm and on the base end side a large-diameter portion having an outside diameter ranging from about 2.6 mm to 3.0 mm. The inner sleeve is inserted in the small-diameter portion and is fixed thereto by means of strap-like tabs. A holder is fixed around the outer peripheral portion of the large-diameter portion, and is assembled in a ceramic disk via the holder.

Abstract: An electron gun comprising at least one cathode for emitting electrons, a cylindrical device, a first electrode layer provided on the cathode side of inner surface of the cylindrical device, a second electrode layer provided on a panel side of inner surface of the cylindrical device, and a third electrode layer provided between the first electrode layer and the second electrode layer, a ratio of a gap between the second electrode and the third electrode to a gap between the first electrode and the third electrode being defined more than 1, wherein the ratio of the gap between the second electrode and the third electrode to the gap between the first electrode and the third electrode is 1:1 to 2, the cylindrical device is made of ceramic, and further comprising at least one resistive layer provided on the inner surface of the cylindrical device, and at least one conductive layer provided between the adjacent electrode layers.

Abstract: An electron gun without deviation of diameter between grids, having a good object point diameter shape, and having a high cut-off voltage, which is cheap and has high performance, and a cathode ray tube provided with the same. The electron gun is provided with a spacer of a columnar shape which has surfaces facing each other on its two end surfaces, a beam aperture penetrating the spacer between the end surfaces, and conductive films provided on the two end surfaces, in which at least the circumferential wall of the beam aperture is constituted by a high resistance conductive material, the conductive films being used to constitute the grids and the beam aperture being constituted as an aperture for an electron beam.

Abstract: An electron gun comprising at least one cathode for emitting electrons, a cylindrical device, a first electrode layer provided on the cathode side of inner surface of the cylindrical device, a second electrode layer provided on a panel side of inner surface of the cylindrical device, and a third electrode layer provided between the first electrode layer and the second electrode layer, a ratio of a gap between the second electrode and the third electrode to a gap between the first electrode and the third electrode being defined more than 1, wherein the ratio of the gap between the second electrode and the third electrode to the gap between the first electrode and the third electrode is 1 to 2, the cylindrical device is made of ceramic, and further comprising at least one resistive layer provided on the inner surface of the cylindrical device, and at least one conductive layer provided between the adjacent electrode layers.

Abstract: In an electron gun for a CRT in which a plurality of cylindrical electrodes are arranged and fixed in series to control a path of electron beams emitted from a cathode, a cylindrical support member is disposed between at least two adjacent cylindrical electrodes so that the two cylindrical electrodes are arranged coaxially. One end portion of the cylindrical support member and one cylindrical electrode are fixed to each other by fitting the former into the latter or vice versa, and the other end portion of the cylindrical support member and the other cylindrical electrode are fixed to each other by fitting the former into the latter or vice versa.